1. Field of the Invention
The present invention relates to bridge deck modules fabricated using fiber reinforced polymer composite materials having a polygonal tubular cross-section and having a snap-fit connections, and it also relates to fiber reinforced polymer composite bridge decks constructed using such bridge deck modules.
2. Description of the Prior Art
As an alternative to reinforced concrete bridge deck, fiber reinforced composite bridge deck with lightweight, high strength and high durability has been proposed. U.S. Pat. No. 6,467,118 discloses a load bearing deck structure being made of at least one sandwich panel which comprises a plurality of hollow, elongated core members having side walls, the core members being provided with an upper facesheet and a lower facesheet.
Further, U.S. Pat. No. 6,591,567 discloses a lightweight fiber reinforced polymer composite decks having a fiber reinforced polymer composite module that interlocks with other similarly designed module. FIGS. 1A and 1B in this specification correspond to FIGS. 1 and 4 disclosed in U.S. Pat. No. 6,591,567, respectively. The module 100 disclosed in U.S. Pat. No. 6,591,567 is designed as having a male end 132 and a female end 134 such that adjacent module interlock together by inserting the male end 132 into the female end 134 of the adjacent module. Therefore, the bridge deck 400 is created by interlocking together two or more modules 100 with adhesives.
Meanwhile, in the case of bridge deck 400, a shear connection between the bridge deck and a girder should be provided to have composite action with girder. Generally, in order to connect the deck to the girder integrally, shear connectors such as shear studs are provided on the top of the girder.
In FIGS. 1A and 1B, in order to fabricate the deck 400 with the deck modules 100, a deck module 100, in which adhesives are applied in the tongue and groove parts, should be pushed into a horizontal direction to assemble. Further, in FIG. 1B, in order to connect the deck 400 side by side on the top of the girder 402, the deck 400 should also be glued at connecting tongue and groove part, and it is pushed horizontally so that it is assembled with the neighboring deck 400. In this way, therefore, shear connectors, positioned in vertical direction on the top of the girder, could not be provided until the decks 400 are assembled completely. This is because if shear connectors has already been provided on the top of the girder 402 prior to the assemblage of the deck, the deck 400 could not be pushed horizontally to the adjacent deck. However, if the shear connectors are provided after the assemblage of the deck, the following inconveniences can be accompanied.
First, it is inconvenient that the shear connectors should be installed from the top of the deck through the pre-drilled hole in the deck at the construction site after the deck 400 has been assembled. When the girder 402 is made of steel, it is preferable to install the shear connectors on the upper flange of the girder 402 through welding before the girder 402 is in place. In such structure of the prior art however, the shear connectors could not be installed beforehand but had to be directly installed through confined small working hole at a place only after girder 402 is in place. This causes bad workability in the site and takes much time, effort and costs in installing decks.
Second, if composite deck is used for the purpose of replacing deteriorated concrete deck of the bridge, to install composite deck of such tongue and groove type horizontally on the top of the existing girder, the shear studs welded at the top of the girder should be removed after dismantling the concrete deck. Then, after installation of composite deck, new shear studs should be installed again through the hole of the deck to connect to existing girder of the bridge. In this case, it takes double costs in removal and reinstallation of the shear connectors.
Third, for such composite deck of tongue and groove type, adhesives should be used to bond modules and decks to each other. However, in such case, when disjointing and removing of the deck is necessary for reuse or repair purpose, it is nearly impossible to cleanly break up the deck.
Fourth, since welding of shear connectors to girder for such composite deck of tongue and groove type is done from the top of the deck through the drilled small hole generally with stud gun, construction workability is bad, and quality control of welding is difficult.
Fifth, if the girder is made of concrete, work for deck connection to girder at site is far more difficult. In this case, after placement of the deck on the top of the girder, shear bars of channel type are installed through the small working hole in the deck. Prior to installation of shear bars, drilling of bar holes in the concrete girder through the small hole of the deck is inevitable. Inserting shear bars into this hole at the girder and adhesive grouting are followed. Construction workability of this process is very bad and moreover, the reinforcing bar or prestressing tendon in the concrete girder might be in danger of cut during drilling holes and it may jeopardize the structural safety of the bridge. Further, quality control of this type work is very difficult.
In the prior art in which the deck module 100 should be pushed in a horizontal direction on the top of the girder 402 in order to assemble the deck 400, many problems as described above can be arisen.
Meanwhile, in the deck module of U.S. Pat. No. 6,591,567 as shown in FIGS. 1A and 1B, adhesive bonding between the male end 132 and the female end 134 is necessary for integral action of the assembled deck. However, the durability of the adhesive is not yet verified completely, and it cannot be guaranteed through the long life time of bridge. Also, the adhesive such as epoxy requires considerable curing time, and it takes relatively long construction time for deck assemblage compared to connection methods other than bonding. Particularly, if the deck modules are connected with each other by use of adhesives, it can hardly be disassembled in order for repair or reuse in the later time.
Since composite bridge deck module mentioned above is only for straight bridge and does not have function to make a curved shape in the horizontal plan, it has drawback not to be applicable to the curved bridge.